Kconfig: Migrate CONFIG_BAUDRATE

Move this in to Kconfig with a default of 115200.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
[trini: Run moveconfig.py, reword commit slightly]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/gr_xc3s_1500_defconfig b/configs/gr_xc3s_1500_defconfig
index 9f1d6a8..ecf0886 100644
--- a/configs/gr_xc3s_1500_defconfig
+++ b/configs/gr_xc3s_1500_defconfig
@@ -7,3 +7,4 @@
 # CONFIG_CMD_SETEXPR is not set
 CONFIG_CMD_PING=y
 CONFIG_MTD_NOR_FLASH=y
+CONFIG_BAUDRATE=38400